Steven M. Neustein

Intraoperative Transesophageal Echocardiography During Noncardiac Surgery

OBJECTIVE To investigate the use and impact of transesophageal echocardiography (TEE) during noncardiac surgery. DESIGN Retrospective study. SETTING A university teaching hospital. PARTICIPANTS AND INTERVENTIONS The medical records and the videotapes of 123 intraoperative TEE examinations were reviewed. MEASUREMENTS AND MAIN RESULTS TEE was used for non-consultative indications in 68 patients and in consultation in 55 patients. Information that would not have been detected intraoperatively by other means included intracardiac defects, valvular and aortic pathology, the presence or absence of ventricular dysfunction or intracardiac thrombi, and embolization during surgery. Findings during the initial TEE examination and the TEE evaluation of intraoperative events resulted in a major impact on patient management in 15% of patients. The majority of patients in whom TEE had any impact (the sum of major, minor, and limited impact groups) were classified as American Society of Anesthesiologists (ASA) class 3 or 4. Patients in whom TEE had any impact were significantly older than patients in whom TEE had no impact (66.5 +/- 13.4 years v 58.1 +/- 16.2 years; p < 0.05). No patient experienced a complication related to intraoperative TEE. CONCLUSION It appears that TEE in patients undergoing noncardiac surgery is efficacious in rapidly disclosing new findings and information during periods of hemodynamic instability. It may have a significant impact on intraoperative patient management and may be beneficial in patients older than 66 years of age.

Haemodynamic response to induction of anaesthesia with ketamine/midazolam

The haemodynamic responses following induction of anaesthesia with ketamine and midazolam have not been determined previously. Twenty adult patients for elective myocardial revascularization were randomized to two regimens for induction of anaesthesia. Patients in Group I received ketamine, 2 mg·kg−1, and midazolam, 0.2 mg·kg−1 and those in Group II received ketamine, 2 mg·kg−1, and midazolam, 0.4 mg·kg−1. Measurements were recorded at baseline, 1 min postinduction, and at one, three, five and ten minutes after tracheal intubation. Tachycardia and hypertension (>20% increases from awake baseline values) were treated with esmolol, 250 μg·kg−1. There were 11 patients in Group I and nine patients in Group II. There were no significant intergroup differences in demographic or haemodynamic variables. Both groups had decreases (P<0.05), in stroke volume, pulmonary capillary wedge pressure, and right ventricular end-diastolic volume at multiple study intervals following anaesthetic induction. None of these changes required clinical intervention. Five patients (all in Group Il) had hypertensive responses to tracheal intubation. Preoperative hypertension (mean arterial pressure ≥100 mmHg) was a predictor (P<0.05) of a hypertensive response to intubation, independent of the midazolam dose. Intravenous ketamine and midazolam was associated with a high incidence (25%) of haemodynamic responses to tracheal intubation. The higher dose of midazolam did not provide any haemodynamic advantage.RésuméLa réponse hémodynamique après induction de l’anesthésie avec kétamine et midazolam n’a pas été déterminée à date. Vingt patients adultes, pour une chirurgie de revascularisation myocardique, furent randomisés en deux groupes. Le groupe I a reçu de la kétamine 2 mg·kg−1, et du midazolam 0,2 mg·kg−1 alors que le groupe II a reçu de la kétamine 2 mg·kg−1 et du midazolam 0,4 mg·kg−1. Les mesures furent enregistrées avant l’induction, une minute post-inductiion, et à trois, cinq et dix minutes après l’intubation trachéale. La tachycardie et l’hypertension (>20% des valeurs de base après induction) furent traitées avec de l’esmolol, 250 μg·kg−1. Il y avait Il patients dans le groupe I et neuf patients dans le groupe II. Il n’y avait aucune différence significative entre les groupes dans les données démographiques et les variables hémodynamiques. Les deux groupes avaient une diminution significative (P<0,05) dans le volume d’éjection, la pression capillaire pulmonaire bloquée, le volume en fin de diastole du ventricule droit aux différents intervalles de l’étude après induction de l’anesthésie. Aucun de ces changements n’a requis une intervention clinique. Cinq patients (tous du groupe II) ont présenté une hypertension lors de l’intubation. L’hypertension préopératoire (pression artérielle moyenne ≥ 100 mmHg) pouvant prédire (P<0,05) la réponse hypertensive lors de l’intubation et indépendamment de la dose de midazolam. L’administration intraveineuse de kétamine et de midazolam fut associée à une inducence élevée (25%) de réponse hémodynamique lors de l’intubation. La dose élevée de midazolam n’a pas fourni d’avantage hémodynamique.

Intrathecal morphine during thoracotomy, part II: Effect on postoperative meperidine requirements and pulmonary function tests

The ability of intrathecal morphine (ITM) to reduce post-thoracotomy pain and meperidine requirements was investigated. Thirty adult patients scheduled for thoracic surgery were studied. Following induction with thiamylal sodium and succinylcholine, anesthesia was maintained with 100 micrograms of fentanyl, vecuronium, and enflurane. Prior to skin incision, 16 patients received intrathecal morphine, 12 micrograms/kg, injected at the L3-4 or L4-5 level. The other 14 patients were controls. Postoperatively, patients were evaluated for pain scores and the total doses of meperidine required over 24 hours. The patients in the ITM group required significantly less meperidine compared to the control group (59 +/- 68 v 167 +/- 97 mg, respectively) and had lower pain scores (1.4 +/- 1.1 v 2.4 +/- 0.9 mg, respectively). There were no serious side effects attributable to ITM. It is concluded that ITM is an effective adjunctive treatment for control of post-thoracotomy pain.

Transesophageal Doppler echocardiographic monitoring for malperfusion during aortic dissection repair

Abstract The present case of cardiopulmonary bypass malperfusion demonstrates the usefulness of transesophageal Doppler echocardiographic monitoring during repair of acute aortic dissection.

Incidence of malposition of polyvinylchloride and red rubber left-sided double-lumen tubes and clinical sequelae

Currently, fiberoptic bronchoscopy (FB) is recommended for correct positioning of double-lumen endobronchial tubes (DLTs) because of the high incidence of malpositions not appreciated by clinical signs. The aims of this study were to assess whether clinical signs allow accurate confirmation of adequate positioning with left red rubber (RR) or polyvinylchloride (PVC) double-lumen tubes and to compare the incidence of malpositions between the two tubes. Another goal was to assess whether these malpositions, not appreciated by clinical assessment, adversely affected outcome. Twenty-one adult patients scheduled for elective thoracic surgery were randomly assigned to the RR (11 patients) or PVC group (10 patients). After endobronchial intubation, the position of the tubes was adjusted until clinically satisfactory lung separation had been achieved. A single investigator performed all the FB and assessed adequacy of tube placement. Clinical and FB assessments were performed in the supine (SUP) and lateral positions. The anesthesiologists responsible for the clinical evaluation were “blinded” to the bronchoscopic findings. While in the SUP position, the tube was “too deep” to permit visualization of the carina during tracheal bronchoscopy in 5 patients (2 RR, 3 PVC). In 17 of 21 (10 RR, 7 PVC), the bronchial cuff could not be visualized, although in 1 patient (RR group), the cuff was overinflated and bulged out to partially obstruct the right main bronchus orifice. Bronchial bronchoscopy showed 4 of 11 patients in the RR group in whom the left upper lobe orifice was occluded compared with 1 only in the PVC group. The PVC did not differ from the RR in cases in which the tube was “too far out.” However, they did differ in the incidence of the tube being pushed too far in 36% in the RR versus 10% in the PVC ( p 2 , PaCO 2 , tidal volume, and the peak airway pressures in all the patients in the PVC versus the RR DLT groups show no differences between the 2 groups. In the cases of malpositioned tubes, there were no statistical differences in PaO 2 between the right and left thoracotomies during two-lung ventilation (2LV) or one-lung ventilation (OLV) (520 ± 80 v 469 ± 56 mmHg and 167 ± 105 v 325 ± 94 mmHg, respectively). In the well-positioned tubes, the comparison between right and left thoracotomies showed no statistical differences in PaO 2 , (432 ± 114 v 464 ± 71 mmHg during 2LV and 182 ± 104 v 157 ± 94 mmHg during OLV, respectively). The results of this study show that, first, there is no significant difference in ventilation between the PVC and the RR tubes as measured by PaCO 2 , peak airway pressure, and tidal volume. Second, a similar incidence of malpositions was found in both groups in the supine and lateral decubitus positions except for a higher incidence of malposition in the RR group in which the bronchial carina was not visualized during bronchial bronchoscopy. Finally, the patients with malpositioned tubes had similar arterial oxygen saturation to patients with well-positioned tubes, whether the patients were undergoing right or left thoracotomies.

Intrathecal morphine during thoracotomy, part 1: Effect on intraoperative enflurane requirements

The ability of intrathecal morphine to reduce the anesthetic requirements during thoracotomy was investigated. Twenty-four patients scheduled for thoracic surgery were studied. Anesthesia was induced with thiamylal sodium, 4 mg/kg, fentanyl, 100 micrograms, and 100 mg of succinylcholine. Prior to skin incision, 12 patients received intrathecal injection of 12 micrograms/kg of preservative-free morphine sulfate (ITM), while the remaining 12 patients served as controls. The ITM was given undiluted at the L3-4 or L4-5 level. Anesthesia was maintained solely with enflurane, titrated to keep mean arterial pressure within 15% of the preoperative values. Vecuronium was given as required for relaxation. No additional narcotics were administered. Throughout the procedure, end-tidal (ET) enflurane concentration was recorded at 15-minute intervals from the mass spectrometer (Perkin Elmer). The intraoperative mean ET concentration of enflurane was significantly reduced in the ITM group beginning 1 hour after the injection (1.19 +/- .45% in the control group versus 0.73 +/- 0.08% in the ITM group). The enflurane requirements, expressed as percent end-tidal enflurane/hour, were significantly less in the ITM group for the duration of the procedure (0.8 +/- .17 v 1.08 +/- .22, respectively). In conclusion, when administered prior to skin incision for post-thoracotomy pain control, intrathecal morphine reduces intraoperative enflurane requirements.

The Use of Bronchial Blockers for Providing One-Lung Ventilation

BSOLUTE INDICATIONS FOR providing one-lung ventilation (OLV) include the isolation of one lung to avoid the contamination of a contralateral lung from either blood or infectious material or to provide positive-pressure ventilation to one lung in the presence of either a bulla or bronchopleural fistula in the other lung. Additional indications for OLV are to facilitate surgery in cases such as video-assisted thoracoscopy (VAT), lung resections, esophageal surgery, thoracic spine surgery, and open repair of the descending thoracic aorta. Surgeries using VAT, in particular, require OLV because the surgeon has limited ability to otherwise retract and operate on the lung. These indications are summarized in Table 1.

Milrinone is superior to epinephrine as treatment of myocardial depression due to ropivacaine in pigs.

Purpose: To determine whether milrinone is more effective than epinephrine in the resuscitation of ropivacaine induced cardiotoxicity in pigs.Methods: Arterial, pulmonary, and LVdP/dt catheters were placed in 12 anesthetized, intubated and mechanically ventilated pigs. They received ropivacaineiv to cardiovascular toxicity: 50% decrease in LVdP/dt, cardiac output and mean arterial pressure (MAP). Group 1 (n=6) was treated with 100 µg·kg−1 milrinoneiv, and Group II (n=6) received 0.5 mg epinephrineiv. Resuscitation was successful if cardiac output returned to baseline, and MAP reached 80% of baseline.Results: After ropivacaine, MAP decreased from 88±7 to 49±8 mmHg (P<0.05), CO decreased from 2.8±0.4 to 1.2±0.2 L·min−1 (P<.05), HR decreased from 103±8 to 74±7 beats·min (P<0.05) and LVdp/dt decreased from 1950±130 to 755±125 mmHg (P<0.05). The LV EDP increased from 5±1 to 8±1 mmHg (P<0.05) and SVR from 2317 to 3000±120 dynes·sec−1·cm−5. Electrocardiogram changes included increases in the QTU interval and QRS duration. In all animals, milrinone restored MAP, CO, SV, HR, and dP/dt to baseline and no animal developed arrhythmias. In contrast, epinephrine produced severe hypertension and tachycardia. There was no improvement in CO or SV, and SVR increased. Epinephrine caused A-V dissociation and ventricular arrhythmias in three animals.Conclusion: Milrinone, was more successful than epinephrine in resuscitating anesthetized pigs from ropivacaine-induced cardiovascular toxicity.RésuméObjectif: Déterminer si la milrinone est plus efficace que l’épinéphrine au moment de réanimer des porcs victimes d’une cardiotoxicité induite par la ropivacaïne.Méthode: Des cathéters artériels, pulmonaires et ventriculaires gauches (dP/dtVG) ont été mis en place chez 12 porcs anesthésiés, intubés et sous ventilation mécanique. Ils ont reçu de la ropivacaïneiv qui a provoqué la cardiotoxicité manifestée par: une baisse de 50 % dP/dtVG, du débit cardiaque (DC) et de la pression artérielle moyenne (PAM). Le groupe I (n=6) a été traité avec 100µg·kg−1 de milrinoneiv et le groupe II (n=6) avec 0,5 mg d’épinéphrineiv. La réanimation était réussie lorsque le DC revenait aux valeurs de base et que la PAM atteignait 80 % des valeurs de base.Résultats: Après l’administration de la ropivacaïne, la PAM a chuté de 88±7 à 49±8 mmHg (P<0,05), le DC de 2,8±0,4 à 1,2±0,2 L·min−1 (P<0,05), la FC de 103±8 to 74±7 battements·min (P<0,05) et dP/dtVG de 1950±130 à 755±125 mmHg (P<0,05). La pression télédiastolique du VG a augmenté, passant de 5±1 à 8±1 mmHg (P<0,05) et la résistance vasculaire périphérique (RVP) de 2317 à 3000±120 dynes·s−1·cm−5. Les changements à l’électrocardiogramme comprenaient des augmentations de l’intervalle QTU et de la durée de QRS. Chez tous les animaux, la milrinone a ramené la PAM, le DC, le débit systolique (DS), la FC et dP/dt aux valeurs de base et aucun animal n’a présenté d’arythmie. Par ailleurs, l’épinéphrine a produit une sévère hypertension et de la tachycardie. Il n’y a pas eu d’amélioration du DC ou du DS et la RVP a augmenté. L’épinéphrine a aussi causé une dissociation AV et des arythmies ventriculaires chez trois animaux.Conclusion: La milrinone a été plus efficace que l’épinéphrine pour la réanimation de porcs anesthésiés qui ont subi une cardiotoxicité provoquée par de la ropivacaïne.

Advancing the endotracheal tube smoothly when using the GlideScope

To the Editor: I read, with interest, the article entitled, “A maneuver to facilitate endotracheal intubation using the GlideScope®”.1 In the case of a small mouth opening, the authors recommend inserting the blade of the GlideScope (Verathon, Bothell, WA, USA) from the left side of the mouth. To illustrate this technique, the authors include a photograph revealing a larynx in a deviated position. In Image C, it appears that the angling of the blade to the left might impede passage of the endotracheal tube. Having used the GlideScope extensively, I have also encountered difficulty in establishing adequate space for the endotracheal tube, and I have determined two successful approaches. Firstly, to obtain a view of the vocal cords, the GlideScope can be inserted in the midline. Then, if there is insufficient room in the oropharyngeal cavity to pass the endotracheal tube, the entire GlideScope handle can be shifted to the left to allow passage of the tube. Next, the GlideScope can be readjusted back to the midline to provide the usual laryngeal view. Another approach is to pass the endotracheal tube in the mouth under direct vision, but prior to placement of the GlideScope handle. The authors report some difficulty in passing the endotracheal tube in 25 of 120 patients; however, they do not describe their actual technique and they do not indicate, in how many of these patients, tracheal intubation was unsuccessful. For my part, I have found it much easier to advance the tube by using the GlideScope rigid stylet which features a 90° curve. As the tube is being advanced through the vocal cords, it is rotated 90° clockwise. The stylet is simultaneously pushed out with the thumb to assist in placement of the endotracheal tube. Steven M. Neustein MD Mount Sinai Medical Center, New York, USA E-mail: steve.neustein@msnyuhealth.org Accepted for publication February 20, 2008.

Transesophageal echocardiographic artifact mimicking an aortic valve tumor

T HE intraoperative use of transesophageal echocardiography (TEE) has become a very common practice; the number of patients studied while under anesthesia has been estimated at more than 10,OOO.t Prebypass echocardiography has been reported to either assist or change the planned operation in 29 of 154 patients (19%) scheduled for cardiac valve surgery.2 Accurate interpretation of the echocardiogram requires an understanding of the physics of ultrasound imaging and Doppler techniques, and the identification of artifacts.” A case is presented in which the presence of an artifact resembling a mass prompted an aortic root exploration in a patient undergoing a coronary artery bypass graft (CAESG) operation.